Trooping the Color
Most mere mortals have one birthday per year but the queen has two. The second of these see the Trooping the Color ceremony takes place outside of Buckingham Palace. This is a military ceremony where infantry soldiers and cavalry march past in classic ceremonial uniforms.
Queen Elizabeth was the official supreme commander of the U.K.’s armed forces. She has it within her power to declare war on another nation but never does so of her own accord. The defining moment of the ceremony witnessed the Queen salute her armed forces (via Tatler).